Failure to receive prescribed imaging is associated with increased early mortality after injury in Cameroon

Despite having the highest rates of injury-related mortality in the world, trauma system capacity in sub-Saharan Africa remains underdeveloped. One barrier to prompt diagnosis of injury is limited access to diagnostic imaging. As part of a larger quality improvement initiative and to assist priority setting for policy makers, we evaluated trauma outcomes among patients who did and did not receive indicated imaging in the Emergency Department (ED). We hypothesize that receiving imaging is associated with increased early injury survival. We evaluated patterns of imaging performance in a prospective multi-site trauma registry cohort in Cameroon. All trauma patients enrolled in the Cameroon Trauma Registry (CTR) between 2017 and 2019 were included, regardless of injury severity. Patients prescribed diagnostic imaging were grouped into cohorts who did and did not receive their prescribed study. Patient demographics, clinical course, and outcomes were compared using chi-squared and Kruskal-Wallis tests. Multivariate logistic regression was used to explore associations between radiologic testing and survival after injury. Of 9,635 injured patients, 47.5% (4,574) were prescribed at least one imaging study. Of these, 77.8% (3,556) completed the study (COMPLETED) and 22.2% (1,018) did not receive the prescribed study (NC). Compared to COMPLETED patients, NC patients were younger (p = 0.02), male (p<0.01), and had markers of lower socioeconomic status (SES) (p<0.01). Multivariate regression adjusted for age, sex, SES, and injury severity demonstrated that receiving a prescribed study was strongly associated with ED survival (OR 5.00, 95% CI 3.32–7.55). Completing prescribed imaging was associated with increased early survival in injured Cameroonian patients. In a resource-limited setting, subsidizing access to diagnostic imaging may be a feasible target for improving trauma outcomes.


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Thank you for the clarification. We have removed the trademark symbol from our manuscript (References,item 9,. 5. In the online submission form, you indicated that "Data available upon request from the authors". All PLOS journals now require all data underlying the findings described in their manuscript to be freely available to other researchers, either 1. In a public repository, 2. Within the manuscript itself, or 3. Uploaded as supplementary information. This policy applies to all data except where public deposition would breach compliance with the protocol approved by your research ethics board. If your data cannot be made publicly available for ethical or legal reasons (e.g., public availability would compromise patient privacy), please explain your reasons by return email and your exemption request will be escalated to the editor for approval. Your exemption request will be handled independently and will not hold up the peer review process, but will need to be resolved should your manuscript be accepted for publication. One of the Editorial team will then be in touch if there are any issues.
Thank you. We have uploaded our de-identified dataset entitled "CTR_Radiology_PLOS_Deidentified.xslx" as a supplementary file.
Reviewer 1: 1. "70 reportedly at least one government-funded imaging center in each of Cameroon's 10 geopolitical 71 regions offers computed tomography, imaging capacity is largely concentrated in three major 72 urban areas: Yaoundé, Douala, and Bafoussam. Over 80% of Cameroonian imaging centers are 73 limited to radiographs and/or ultrasound. Most existing equipment is donated, refurbished, or has 74 been in use for over 10 years." The above statement requires a citation (Lines 70-74).
We would like to thank the reviewers for their comment. We have added the citation to the manuscript (Reference section, item 15, line 76).

Ethics Statement "Verbal consent was obtained by research assistant" (Line 97)
This raises some concern of data safety. What is the procedure for obtaining consent for use of the registry? It is unlikely that it would be standard procedure to obtain verbal permission from Cameroon NEC, and UCLA Institutional Review Boards for use of this data. Authors should kindly review this, and provide an exemption IRB certificate or documented Ethics Approval at the least. If no formal permission has been obtained, the authors should consider a retrospective approval so as to confirm that local partners are agreed to the use of this data. This is a major concern affecting the reviewer decision.

Lines 111-112-"access to liquid petroleum gas (LPG) was used as a surrogate indicator of higher socioeconomic status" The limitations of using this should be highlighted in limitations as more accurate measures of SES could have been collected.
We would like to thank the reviewers for their comment. We completely agree with the reviewer that LPG utilization is only an indicator, and certainly not a comprehensive evaluation, of socioeconomic status in our study population. Our group has previously published methodology for using LPG utilization and four other demographic and health survey indicator questions to generate socioeconomic clusters that correlate tightly with socioeconomic outcome metrics in Cameroon. To increase clarity, we have emphasized that LPG use is only an indicator and provided greater detail and a citation to the methods (line 125) and limitations sections (lines 304-306. Table 1. Demographics of Injured Patients Authors suggest missing demographics data in limitations but no recourse is made to how this was handled. Are these percentages of the total (n)-in which case, no demographics data is missing-or percentages of varying (n)s based on data is available for each demographic consideration? Authors to please clarify in the text or in the case of handling of missingness, in the table.

Line 135
We would like to thank the reviewers for their comment. In cases of data missingness, we used variable n values and clarified this recourse in the limitations section (Limitations,.

Line 136 IQR, interquartile range. IQR is not referenced in table 1 and should not be in the footnotes
We would like to thank the reviewers for their comment. We reference IQR with median age in Table 1.
6. 173 to 174-The authors noted that "NC patients reported significantly higher rate of cost interference with care (60.5%) compared to COMPLETED" Could this be because patients could afford the investigations? A higher capacity to pay results in better care and not just in receipt of more imaging which implies a likelihood to progress in care. As NC patients reported a "significantly higher rate of cost interference with care (60.5%) compared to COMPLETED patients" Line 181-"NC patients left against medical advice (35.0% vs. 21.3%, p<0.01) or died (5.6% vs. 1.3%, 182 p<0.01) more frequently" Authors should look into the sequence-did NC have less imaging because they died before imaging was possible? or left against medical advice before imaging was available? Or physicians considered it medical futility to carry out some investigations in these patients? Is there a threshold of days on admission considered, as a subset of the analysis to ensure that early deaths do not confound these results? Can this be emphasized? Kindly add in a time to death (in NC) versus time to intervention in C to clarify.
We would like to thank the reviewers for their questions. We absolutely agree that all of these suggestions are possibilities. Unfortunately, a notable limitation of the observational methodology employed in this study is that it is not possible to infer causality between these associated events. We hypothesize that inability to pay is indeed a significant contributing factor in both failure to complete prescribed imaging and in failure to receive other types of care, all of which likely contribute to poor outcomes including increased rates of death. To support scaling efforts, we think it is critical to further explore the impact on patient outcomes when diagnostic imaging is available by performing a controlled clinical trial. We also hypothesize that there is likely some survivorship bias to completing prescribed imaging among those who do not die or leave against medical advice. However, we still feel the association highlights a critical and possibly actionable care delivery deficit in the Cameroon Trauma System as in developed trauma settings, diagnostic imaging (radiographs and point-of care ultrasonography) is performed as a part of the initial trauma survey and assessment, within the first minutes of the patient presenting for evaluation. Average time to death in the whole study cohort was 3.9 hours, which in an optimized setting would provide ample time for completion of at least some imaging. We have added data on time to intervention and death in results (Results, and emphasized these points in our discussion (Discussion,. 7. Line 185 "Time to disposition did not differ significantly between cohorts." In consideration of significance-Even if it did not differ significantly, did time to disposition differ at all? Kindly state the difference if any (means)and p-value. Perhaps some issues are not statistically significant but might be clinically significant.
We would like to thank the reviewers for their comment. For additional clarity, we have added the medians with a p-value for clarification (Results,.
8. Authors should confirm-Is there the possibility that point of care focused assessment sonography for trauma might have been missed in the registry records? Bedside/ED ultrasound scan in some LMICs, by experience, is usually not ordered or documented as a radiological "procedure" or standard assessment.
We would like to thank the reviewers for their question. Point-of-care ultrasound was not available at any of the study sites during the study period. For increased clarity, we have added this information to the discussion (Discussion,.
9. Lines 211-212 "In Cameroon, our data suggest that both under-prescription and barriers to imaging completion play a role in the limited utilization of radiology." Underprescription does not appear to be the focus of this study, and should not be emphasized.
We would like to thank the reviewers for their comment. While we fully agree that assessment of imaging underprescription is not the primary objective of our study, we do believe that our data are highly suggestive that underprescription is occurring in this population. We felt that these ancillary findings are important to note briefly as this may also substantially contribute to poor outcomes and should be taken into account when considering development of future prospective clinical trials.
10. The Limitations are excellent observations. Generalizability to other healthcare systems *will* be imperfect, and should be acknowledged as such We would like to thank the reviewers for their comment. We agree and have modified our language to reflect this limitation (Discussion, line 307).

Authors should consider including a reference to the Lancet Commission on Diagnostics as there is much alignment with the intent of this paper-and for suggestions of set standards
We would like to thank the reviewers for their insightful suggestion. We have added this reference to our manuscript (Discussion, lines 256-258, reference 32).

Please edit reference 10 (Line 296)
Thank you. We have modified reference 10.
13. Figure 1-showing what was not completed in Figure 1 would help clarify what specifically is NC (to mirror the completed. Kindly add this in for more clarity on the part of the reader.
We would like to thank the reviewers for their comment. We have modified Figure 1 accordingly and have provided additional detail discussing the differing distribution of performed and non-performed imaging (Results,.
14. Authors should also kindly briefly comment of overutilization of imaging with financial and environmental implications that typically can occur in high resource settings, and where the balance should be, in the discussion.
We would like to thank the reviewers for this insightful suggestion. We have added a brief discussion on maintaining this balance to the discussion section of our manuscript (Lines 277-282).
15. Finally, the authorship order raises a few concerns of LMIC authors being "stuck in the middle." Could authors consider co-first authorship based on other contribution considerations, co-senior authorship, or at the minimum, having a Cameroonian corresponding author, as this work is done on data from Cameroon? there is some reflexivity required here, and the authorship team would do well to consider carefully the inclusive placement of LMIC authors in the hierarchy of authorship.